Cannabinoids in Treating Parkinson’s Disease Symptoms: A Systematic Review of Clinical Studies

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“Background: Parkinson’s disease (PD) is a serious neurodegenerative condition impacting many individuals worldwide. There is a need for new non-invasive treatments of PD. Cannabinoids in the form of cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) may offer utility as treatment, and our objective was hence to conduct a systematic review regarding the clinical evidence for the efficacy and safety of cannabinoids in treating PD. 

Methods: Screening, data extraction, and quality assessments were all conducted by multiple reviewers, with discrepancies resolved by consensus. 

Results: After conducting searches in 4 different databases, 673 articles were screened. Thirteen articles were deemed eligible for inclusion in this review. It was shown that cannabis, CBD, and nabilone (a synthetic form of THC) were capable of consistently improving motor symptoms more than a placebo. All treatments improved various non-motor symptoms, particularly with cannabis improving pain intensity, and CBD improving psychiatric symptoms in a dose-dependent manner. Adverse effects were usually minor, and, in the case of CBD, rare (except at very high doses). 

Conclusion: Cannabinoids have been shown to safely offer important potential in treating motor symptoms in PD and some non-motor symptoms. More large-scale randomized control trials for specific forms of cannabinoid treatments are required to determine their overall efficacy.”

https://pubmed.ncbi.nlm.nih.gov/37253174/

https://www.liebertpub.com/doi/10.1089/can.2023.0023

Therapeutic use of cannabinoids for the treatment of neurodegenerative disorders: a potential breakthrough

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“Marijuana, also known as cannabis, is a plant-based illicit drug notorious for its recreational purposes. However, in recent years its extracts are being extensively studied for their overall therapeutic effects. Active substances found in marijuana that interact with the endocannabinoid system are known as cannabinoids, the primary examples being 9-tetrahydrocannabinol (9-THC) and Cannabidiol (CBD). These cannabinoids ligand to receptors such as CB1 (found in CNS) and CB2 (found in immune system cells) to prevent the release of neurotransmitters and modulate immune cell migration as well as cytokine release, respectively (1). In recent years, there has been a surge of interest in the neuroprotective potential of marijuana; however, investigators could not make firm conclusions about the effectiveness of these treatments. A comprehensive review by Bahji A et al. (2022) found an evident link between cannabidiol-based products and relief from the motor as well as behavioural and psychological symptoms spanning Alzheimer’s disease (AD), Huntington’s disease (HD), and Parkinson’s disease (PD) (2). Here we discuss the effects of marijuana and its derivatives on the treating significant neurodegenerative disorders.

Dronabinol (2.5 mg) seemed to lessen the disordered behaviours as assessed by the Cohen-Mansfield Agitation Inventory in 12 patients of AD (p=0.05) (3). Sherman et al. (2018) reported the association of cannabis administration with weight and pain management in AD patients. The adverse effects are typically well tolerated at the levels supplied, even though cannabis is linked to an increased risk of euphoria, sleepiness and psychosis (1). On the other hand, for HD, nabilone (1 or 2 mg) had a substantial therapeutic benefit in a different 10-week placebo-controlled crossover experiment as determined by the overall motor and chorea score on the Unified Huntington’s Disease Rating Scale (UHDRS) (4). Available reviews revealed variable evidence suggesting the clinical benefits of cannabis in treating motor symptoms in patients with PD. A randomized trial found that compared to a placebo, giving a single dosage of 300 mg of CBD successfully decreased tremor amplitude (5).

Neurological diseases, including  the  neurodegenerative diseases,  comprise  8.7% of the disease burden  in lower- middle- income countries (such as Pakistan) (6). Currently, there is no real cure for neurodegenerative disorders, only symptomatic management, such as dopamine treatment for PD or cholinesterase inhibitors for dementia. Cannabinoids might be the lifeline all neurodegenerative disorder patients have been waiting for.”

https://pubmed.ncbi.nlm.nih.gov/37218269/

https://ojs.jpma.org.pk/index.php/public_html/article/view/7805

Cannabidiol Protects Dopaminergic-like Neurons against Paraquat- and Maneb-Induced Cell Death through Safeguarding DJ-1CYS106 and Caspase 3 Independently of Cannabinoid Receptors: Relevance in Parkinson’s Disease

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“Parkinson’s disease (PD), a progressive neurodegenerative movement disorder, has reached pandemic status worldwide. This neurologic disorder is caused primarily by the specific deterioration of dopaminergic (DAergic) neurons in the substantia nigra pars compacta (SNc). Unfortunately, there are no therapeutic agents that slow or delay the disease progression. Herein, menstrual stromal cell-derived dopamine-like neurons (DALNs) intoxicated with paraquat (PQ2+)/maneb (MB) were used as a model system to elucidate the mechanism by which CBD protects the neural cell from apoptosis in vitro. According to immunofluorescence microscopy, flow cytometry, cell-free assay, and molecular docking analysis, we demonstrate that CBD offers protection to DALNs against PQ2+ (1 mM)/MB (50 μM)-induced oxidative stress (OS) by simultaneously (i) decreasing reactive oxygen species (ROS: O2•-, H2O2), (ii) maintaining the mitochondrial membrane potential (ΔΨm), (iii) directly binding to stress sensor protein DJ-1, thereby blunting its oxidation from DJ-1CYS106-SH into DJ-1CYS106-SO3, and (iv) directly binding to pro-apoptotic protease protein caspase 3 (CASP3), thereby disengaging neuronal dismantling. Furthermore, the protective effect of CBD on DJ-1 and CASP3 was independent of CB1 and CB2 receptor signaling. CBD also re-established the Ca2+ influx in DALNs as a response to dopamine (DA) stimuli under PQ2+/MB exposure. Because of its powerful antioxidant and antiapoptotic effects, CBD offers potential therapeutic utility in the treatment of PD.”

https://pubmed.ncbi.nlm.nih.gov/37220279/

https://pubs.acs.org/doi/10.1021/acschemneuro.3c00176

Long-term safety of medical cannabis in Parkinson’s disease: A retrospective case-control study

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“Background: Whole-plant medical cannabis (MC) products are widely used for controlling symptoms associated with Parkinson’s disease (PD). Despite its widespread use, few studies have investigated the long-term impact of MC on the progression of PD or its safety profile. This study examined the effects of MC on PD in a real-life setting.

Methods: A retrospective case-control study of 152 idiopathic PD patients (mean age 69.1 ± 9.0 years), followed at the Sheba Medical Center Movement Disorders Institute (SMDI) from 2008 to 2022 was conducted. Seventy-six patients who used licensed whole-plant medical cannabis (MC) for at least a year were compared to a matched group who did not receive MC in terms of their Levodopa Equivalent Daily Dose (LEDD), Hoehn and Yahr (H&Y) stage, and cognitive, depressive, and psychotic symptoms.

Results: The median monthly dose of MC was 20 g (IQR: 20-30), with a median Tetrahydrocannabinol (THC) percentage of 10 (IQR: 9.5-14.15) and a median Cannabidiol (CBD) percentage of 4 (IQR: 2-10). There were no significant differences between the MC and the control groups for LEDD or H&Y stage progression (p = 0.90, 0.77, respectively). A Kaplan-Meier analysis showed no evidence of relative worsening of psychotic, depressive, or cognitive symptoms reported by patients to their treating physicians over time in the MC group (p = 0.16-0.50).

Conclusion: Over the 1-3 years of follow-ups, the MC treatment regimens appeared to be safe. MC did not exacerbate neuropsychiatric symptoms and had no detrimental effects on disease progression.”

https://pubmed.ncbi.nlm.nih.gov/37211456/

https://www.prd-journal.com/article/S1353-8020(23)00129-3/fulltext

Medical Cannabis in the Treatment of Parkinson’s Disease

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“Objectives: Medical cannabis (MC) has recently garnered interest as a potential treatment for neurologic diseases, including Parkinson’s disease (PD). A retrospective chart review was conducted to explore the impact of MC on the symptomatic treatment of patients with PD.

Methods: Patients with PD treated with MC in the normal course of clinical practice were included (n = 69). Data collected from patient charts included MC ratio/formulation changes, PD symptom changes after initiation of MC, and adverse events (AEs) from MC use. Information regarding changes in concomitant medications after MC initiation, including opioids, benzodiazepines, muscle relaxants, and PD medications, was also collected.

Results: Most patients were initially certified for a 1:1 (∆ 9 -tetrahydrocannabinol:cannabidiol) tincture. Eight-seven percent of patients (n = 60) were noted to exhibit an improvement in any PD symptom after starting MC. Symptoms with the highest incidence of improvement included cramping/dystonia, pain, spasticity, lack of appetite, dyskinesia, and tremor. After starting MC, 56% of opioid users (n = 14) were able to decrease or discontinue opioid use with an average daily morphine milligram equivalent change from 31 at baseline to 22 at the last follow-up visit. The MC was well-tolerated with no severe AEs reported and low rate of MC discontinuation due to AEs (n = 4).

Conclusions: The MC may improve motor and nonmotor symptoms in patients with PD and may allow for reduction of concomitant opioid medication use. Large, placebo-controlled, randomized studies of MC use in patients with PD are required.”

https://pubmed.ncbi.nlm.nih.gov/37191563/

https://journals.lww.com/clinicalneuropharm/Abstract/2023/05000/Medical_Cannabis_in_the_Treatment_of_Parkinson_s.3.aspx

Medical Cannabis in the Treatment of Parkinson’s Disease

Clinical Neuropharmacology

“Objectives: Medical cannabis (MC) has recently garnered interest as a potential treatment for neurologic diseases, including Parkinson’s disease (PD). A retrospective chart review was conducted to explore the impact of MC on the symptomatic treatment of patients with PD.

Methods: Patients with PD treated with MC in the normal course of clinical practice were included (n = 69). Data collected from patient charts included MC ratio/formulation changes, PD symptom changes after initiation of MC, and adverse events (AEs) from MC use. Information regarding changes in concomitant medications after MC initiation, including opioids, benzodiazepines, muscle relaxants, and PD medications, was also collected.

Results: Most patients were initially certified for a 1:1 (∆9-tetrahydrocannabinol:cannabidiol) tincture. Eight-seven percent of patients (n = 60) were noted to exhibit an improvement in any PD symptom after starting MC. Symptoms with the highest incidence of improvement included cramping/dystonia, pain, spasticity, lack of appetite, dyskinesia, and tremor. After starting MC, 56% of opioid users (n = 14) were able to decrease or discontinue opioid use with an average daily morphine milligram equivalent change from 31 at baseline to 22 at the last follow-up visit. The MC was well-tolerated with no severe AEs reported and low rate of MC discontinuation due to AEs (n = 4).

Conclusions: The MC may improve motor and nonmotor symptoms in patients with PD and may allow for reduction of concomitant opioid medication use. Large, placebo-controlled, randomized studies of MC use in patients with PD are required.”

https://pubmed.ncbi.nlm.nih.gov/37071411/

https://journals.lww.com/clinicalneuropharm/Abstract/9900/Medical_Cannabis_in_the_Treatment_of_Parkinson_s.48.aspx

Cannabidiol Recovers Dopaminergic Neuronal Damage Induced by Reserpine or α-synuclein in Caenorhabditis elegans

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“Progressive neurodegenerative disorders such as Parkinson Disease (PD) lack curative or long-term treatments. At the same time, the increase of the worldwide elderly population and, consequently, the extension in the prevalence of age-related diseases have promoted research interest in neurodegenerative disorders. Caenorhabditis elegans is a free-living nematode widely used as an animal model in studies of human diseases.

Here we evaluated cannabidiol (CBD) as a possible neuroprotective compound in PD using the C. elegans models exposed to reserpine.

Our results demonstrated that CBD reversed the reserpine-induced locomotor alterations and this response was independent of the NPR-19 receptors, an orthologous receptor for central cannabinoid receptor type 1. Morphological alterations of cephalic sensilla (CEP) dopaminergic neurons indicated that CBD also protects neurons from reserpine-induced degeneration. That is, CBD attenuates the reserpine-induced increase of worms with shrunken soma and dendrites loss, increasing the number of worms with intact CEP neurons. Finally, we found that CBD also reduced ROS formation and α-syn protein accumulation in mutant worms.

Our findings collectively provide new evidence that CBD acts as neuroprotector in dopaminergic neurons, reducing neurotoxicity and α-syn accumulation highlighting its potential in the treatment of PD.”

https://pubmed.ncbi.nlm.nih.gov/36964823/

https://link.springer.com/article/10.1007/s11064-023-03905-z

A Retrospective Medical Record Review of Adults with Non-Cancer Diagnoses Prescribed Medicinal Cannabis

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“Research describing patients using medicinal cannabis and its effectiveness is lacking. We aimed to describe adults with non-cancer diagnoses who are prescribed medicinal cannabis via a retrospective medical record review and assess its effectiveness and safety. From 157 Australian records, most were female (63.7%; mean age 63.0 years). Most patients had neurological (58.0%) or musculoskeletal (24.8%) conditions. Medicinal cannabis was perceived beneficial by 53.5% of patients.

Mixed-effects modelling and post hoc multiple comparisons analysis showed significant changes overtime for pain, bowel problems, fatigue, difficulty sleeping, mood, quality of life (all p < 0.0001), breathing problems (p = 0.0035), and appetite (p = 0.0465) Symptom Assessment Scale scores. For the conditions, neuropathic pain/peripheral neuropathy had the highest rate of perceived benefit (66.6%), followed by Parkinson’s disease (60.9%), multiple sclerosis (60.0%), migraine (43.8%), chronic pain syndrome (42.1%), and spondylosis (40.0%). For the indications, medicinal cannabis had the greatest perceived effect on sleep (80.0%), followed by pain (51.5%), and muscle spasm (50%). Oral oil preparations of balanced delta-9-tetrahydrocannabinol/cannabidiol (average post-titration dose of 16.9 mg and 34.8 mg per day, respectively) were mainly prescribed. Somnolence was the most frequently reported side effect (21%).

This study supports medicinal cannabis’ potential to safely treat non-cancer chronic conditions and indications.”

“Cannabis (Cannabaceae) has been used medicinally since 400 AD for its analgesic, appetite enhancement, and myorelaxant properties. Emerging evidence suggests that people with chronic conditions may benefit from using medicinal cannabis for treating chronic pain, multiple sclerosis-related spasticity, epilepsy, Parkinson’s disease, insomnia, and anxiety.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9965412/

Machine learning study: from the toxicity studies to tetrahydrocannabinol effects on Parkinson’s disease

“Aim: Investigating molecules having toxicity and chemical similarity to find hit molecules. 

Methods: The machine learning (ML) model was developed to predict the arylhydrocarbon receptor (AHR) activity of anti-Parkinson’s and US FDA-approved drugs. The ML algorithm was a support vector machine, and the dataset was Tox21. 

Results: The ML model predicted apomorphine in anti-Parkinson’s drugs and 73 molecules in FDA-approved drugs as active. The authors were curious if there is any molecule like apomorphine in these 73 molecules. A fingerprint similarity analysis of these molecules was conducted and found tetrahydrocannabinol (THC). Molecular docking studies of THC for dopamine receptor 1 (affinity = -8.2 kcal/mol) were performed. 

Conclusion: THC may affect dopamine receptors directly and could be useful for Parkinson’s disease.”

https://pubmed.ncbi.nlm.nih.gov/36942739/

“A machine learning model was developed to predict AHR activity of anti-Parkinson’s and US FDA-approved drugs separately. The model predicted apomorphine in anti-Parkinson’s drugs, 73 molecules in FDA-approved drugs and tetrahydrocannabinol as active.”

https://www.future-science.com/doi/10.4155/fmc-2022-0181

“Δ⁹-tetrahydrocannabinol (Δ⁹-THC) exerts a direct neuroprotective effect in a human cell culture model of Parkinson’s disease”

https://pubmed.ncbi.nlm.nih.gov/22236282/

Cannabinoids in neuroinflammatory disorders: Focusing on multiple sclerosis, Parkinsons, and Alzheimers diseases

“The medicinal properties of cannabis and cannabinoid-derivative are entirely investigated and known. In addition, the identification of psychotropic plant cannabinoids has led to more studies regarding the cannabinoid system and its therapeutic features in the treatment and management of clinical symptoms of neuroinflammatory disorders, such as multiple sclerosis (MS), Parkinsons disease (PD), and Alzheimers disease (AD). In fact, cannabinoid agonists are able to control and regulate inflammatory responses. In contrast to the cannabinoid receptor type 1 (CB1) and its unwanted adverse effects, the cannabinoid receptor type 2 (CB2) and its ligands hold promise for new and effective therapeutic approaches. So far, some successes have been achieved in this field. This review will discuss an outline of the endocannabinoid system’s involvement in neuroinflammatory disorders. Moreover, the pharmacological efficacy of different natural and synthetic preparations of phytocannabinoids acting on cannabinoid receptors, particularly in MS, PD, and AD, will be updated. Also, the reasons for targeting CB2 for neurodegeneration will be explained.”

https://pubmed.ncbi.nlm.nih.gov/36637897/

https://iubmb.onlinelibrary.wiley.com/doi/10.1002/biof.1936